1. Field of Invention
The present invention relates to a chain, and more particularly to a rolling element chain that can arrange multiple rolling elements at intervals in a line.
2. Description of the Related Art
A rolling element chain is used to keep multiple rolling elements such as balls or cylindrical rollers away from each other to avoid collisions between adjacent rolling elements and prolong life span of the rolling elements. Some rolling element chains can even retain lubricant to lubricate rolling elements.
U.S. Pat. No. 6,155,718 discloses an end-present rolling element chain which has a plurality of balls, interposed portions and connecting portions. The interposed portions are interposed between the balls. The connecting portions connect the interposed portions so as to hold the balls in an arranged condition.
In the conventional chain, each interposed portion has a concave surface and a circular edge engaged with a ball to prevent the ball from falling out from the conventional chain. So, the contact area and the friction between the interposed portion and the ball are quite large. Furthermore, lubricant on the ball may be scraped easily by the circular edge of the interposed portion and a closed space between the concave surface and the ball is defined. Accordingly, replacing lubricant retained in the closed space is hard and the ball can not be lubricated well, even though the concave surface of the interposed portion can retain lubricant.
In addition, the conventional chain is commonly manufactured by injection molding with a combined mold. Because the disengagement travel of the combined mold is perpendicular to the concave direction of the concave surface, this easily causes interference between the mold and the chain and to manufacture the conventional chain is inconvenient.
Another conventional chain as shown in FIG. 1-3 of Taiwan Patent with an issue No. M243590 has multiple rolling elements and separating elements. A receiving hole is defined between adjacent separating elements to receive a rolling element.
However, the separating elements only have a capability of separating the rolling elements but cannot hold the rolling elements securely, so the rolling elements may fall out easily from the conventional chain. When the rolling elements are rolling, the rolling elements are shaking and bumping the separating elements so the friction between the rolling elements and the conventional chain is increased. In addition, lubricant cannot be retained between the rolling elements and the separating elements so the rolling elements cannot be lubricated well.
To overcome the shortcomings, the present invention provides a rolling element chain to mitigate or obviate the aforementioned problems.